3.1 Flashcards
Uniformitarianism
A principal that states that geologic processes that occurred in the past can be explained by current geologic processes
Catasrophism
A principal that states that geologic change occurs suddenly
Paleontology
The scientific study of fossils
Paleontologists
o
Paleobotanists
u
Index fossils
A fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the rock layers
Trace fossils
A fossilized mark that is formed in a soft sediment by the movement of an animal
Cast
A type of fossil that forms when sediments fill in the cavity left by a decomposed organism
Mold
A mark or cavity made in a sedimentary surface by a shell or other body
Geologic Time Scale
The standard method used to divide the Earth’s long natural history into manageable parts
Eon
The largest division of time
Era
A unit of geologic time that includes two or more periods
Period
A unit of geologic time into which eras are divided
Epoch
A subdivision of a geologic period
Extinction
The death of every member of a species
